Her manager, Larry Rudolph, said in a statement late Tuesday that Spears "has been released by the Promises Malibu Treatment Center after successfully completing their program," People magazine said Wednesday.
While at the center, Spears attended Alcoholics Anonymous meetings, though her one-month stay was shorter than the typical 45-day program at Promises.
She voluntarily checked herself into Promises on Feb. 20 after a weekend of hard partying in which she shaved her head. She left the program the next day, but returned when estranged husband Kevin Federline threatened a custody fight over their two boys.
Federline reportedly visited Spears at Promises several times with their sons and has been described as supportive of her recovery.
Spears has custody of the boys and Federline has visitation. While she was in treatment, Federline took care of the children with help from his mother and Spears's mother.